1. Field of the Disclosure
This disclosure generally relates to a control system and, more particularly, to an individualized control system utilizing a biometric characteristic and an operating method thereof.
2. Description of the Related Art
Pulse oximeters utilize a noninvasive method to monitor the blood oxygenation and the heart rate of a user. An optical pulse oximeter generally emits a red light beam (wavelength of about 660 nm) and an infrared light beam (wavelength of about 910 nm) to penetrate a part of the human body and detects an intensity variation of the penetrating light based on the feature that the oxyhemoglobin and the deoxyhemoglobin have different absorptivities in particular spectrum, e.g. referring to U.S. Pat. No. 7,072,701 entitled “Method for spectrophotometric blood oxygenation monitoring”. After the intensity variations, e.g. photoplethysmographic signals or PPG signals, of the penetrating light of the two wavelengths are detected, the blood oxygenation can then be calculated according to an equation: Blood oxygenation=100%×[HbO2]/([HbO2]+[Hb]), wherein [HbO2] is an oxyhemoglobin concentration; and [Hb] is a deoxyhemoglobin concentration.
Generally, the intensity variations of the penetrating light of the two wavelengths detected by a pulse oximeter will increase and decrease with heartbeats. This is because blood vessels expand and contract with the heartbeats such that the blood volume that the light beams pass through will change to accordingly change the ratio of light energy being absorbed. Therefore, the absorptivity of blood of different light spectra can be calculated according to the intensity information changing continuously so as to calculate PPG signals. By further analyzing the PPG signals, biometric characteristics such as the heart rate variability (HRV) and second derivative of photoplethysmogram (SDPPG) are obtainable.
In addition, another kind of electrode type biosensor monitors the biometric characteristics such as the heart rate variability (HRV), electroencephalography (EEG), galvanic skin response (GSR), electrocardiogram (ECG) and electromyography (EMG) by detecting bio-signals.